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Asynchronous Signal Processing for Compressive Data Transmission

Su, Shuang (2011) Asynchronous Signal Processing for Compressive Data Transmission. Master's Thesis, University of Pittsburgh. (Unpublished)

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In this thesis we propose a power-efficient procedure useful in the acquisition of biological data in digital form without using high frequency samplers. The data is compressed so that transmission is limited to parts of the signal that are significant. Our procedure uses an asynchronous sigma delta modulator (ASDM) together with a time-to-digital converter (TDC) to obtain binary data that is transmitted via orthogonal frequency division multiplexing (OFDM). The asynchronous sigma delta modulator is a nonlinear feedback system that allows the representation of bounded signals by zero-crossing times of a binary signal. Using duty-cycle modulation, the ASDM is shown to be equivalent to an optimal level-crossing sampler. The zero-crossing times are measured with a time-to-digital converter that applies pulse-shrinking delay lines and requires no high-frequency clock. Reconstruction of the original signal is possible from the zero-crossing times of the ASDM output binary signal. ASDM time-domain compression is compared with discrete wavelet transform based data compression. For wireless data transmission, the orthogonal frequency division multiplexing (OFDM) reduces the bit error-rate in multipath fading channels. The performance of the proposed algorithm is illustrated using an electrocardiogram signal, which fits the bursty characteristic appropriate for our procedure.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairChaparro, Luis
Committee MemberSun,
Committee MemberMao,
Date: 19 September 2011
Date Type: Completion
Defense Date: 13 July 2011
Approval Date: 19 September 2011
Submission Date: 13 July 2011
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Electrical Engineering
Degree: MSEE - Master of Science in Electrical Engineering
Thesis Type: Master's Thesis
Refereed: Yes
Uncontrolled Keywords: Asynchronous sigma delta modulation; data compression; orthogonal frequency division multiplexing; time-to-digital converter
Other ID:, etd-07132011-172042
Date Deposited: 10 Nov 2011 19:51
Last Modified: 20 Jan 2012 21:11


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